Chair frame



FIG. 1 is a perspective view of a chair frame showing our new design;

FIG. 2 is an alternative perspective view of FIG. 1; and,

FIG. 3 is another alternative perspective view of FIG. 1.

In the drawings, the dashed lines depict portions of the chair frame, which are environment and form no part of the claimed design; the discontinuous long dashes are shading. 

CLAIM The ornamental design for a chair frame, as shown and described. 